The present invention generally relates to electronic control systems for controlling a population of similar, generally independently operated devices. More particularly, it relates to remote control systems for controlling a plurality of electrical devices or apparatuses wherein programming and reference instructions are transmitted to remote, geographically diverse, individual control units, generally provided for each device, so that each individual device may be operated in accordance with predetermined protocols or in accordance with a programmable protocol.
There are many requirements for control systems capable of individually controlling a population of electrical devices in accordance with desired predetermined operating protocols or modes. Control systems may optimize the efficiency of the overall network or population of devices and dramatically reduce energy consumption. Illustrative control systems of the type for controlling a population of devices may include, for example, lighting systems, climate control systems, irrigation/watering systems and traffic control systems, to name but a few. The desired operating protocols implemented by the control system may require the individual devices to operate at designated on-and-off times with respect to a particular time of day, as well as with respect to the length of day, e.g., with respect to sunset or sunrise for the particular geographic location in which the individual electrical device or apparatus is located.
In the following discussion, a new and improved system for controlling a population of individual electrical devices is described with special reference to a preferred context and preferred embodiment relating to lighting of sign boards. Although the invention is described in this context, the new and improved control devices, methods and systems in accordance with this invention are also well suited to other end use environments in lighting applications, in non-lighting applications for climate control, irrigation control, in traffic control and in manufacturing and production applications. Sign board lighting systems are a preferred use relied upon for purposes of illustration and explanation and the invention should not be construed as being limited thereto.
Another example of a system or population of separate devices which is preferably overseen by a common control is a traffic control system. For example, overhead road signs which indicate proper lanes for travel during rush hour may need to be changed to indicate different lane configurations from morning rush hour to evening rush hour. Overhead signs indicating roadway conditions up ahead, indicating delays due to heavy traffic, accidents, weather or construction and the like, possibly indicating alternate routes, may frequently need to be changed. On non-highway streets, the timing of traffic lights may need to be varied at different times of day. For example, on main roads entering or leaving a downtown area, traffic signals may have their timing altered to provide a prolonged green light favoring the direction of heaviest traffic volume. It may be beneficial at rush hour to synchronize a group of adjacent traffic signals to promote maximum flow. It may also be helpful for the prolonged green light signal command to move along a main street with a surge in rush hour traffic. More particularly, at the beginning of rush hour, traffic lights along a major exit route may be changed to provide a span of synchronized long green lights to facilitate faster egress from the city. After the first fifteen minutes, the main surge in traffic volume may now be located at about 10 miles out of the city along the roadway. The lights at this 10-15 mile distance may now be changed to the prolonged green lights and the system may restore the inner city traffic lights back to their normal signal changing cadence or period.
Another example of a control system for controlling a population of individual devices for which the system of this invention may be used may include an irrigation system. In a given irrigation system including a plurality of irrigation booms, it may be necessary or desirable to water crops or lawns after dark to reduce or eliminate water loss due to evaporation. Moreover, it may be important to commence irrigation as soon after sundown as possible to provide maximum soak-in times without evaporation. It may also be important to shut off the water system to prevent over-watering, super-saturation, undesirable flooding or erosion from occurring. Furthermore, watering may need to be performed intermittently, in timed pulses or dosages throughout the hours of darkness for maximum efficiency.
Another example may include a climate control system for a commercial office space, hotel, store or the like, wherein different climate controlled rooms or zones may vary in their heating or cooling requirements depending on their exposure to the sun at various times of day or to their relative zone or room sizes. For example, in the morning, if the outside temperature rises about 75.degree. F., a control system may be needed which turns on the cooling system for a large 2,000 square foot room earlier than a that for a small 300 square foot office to promote efficient energy use in readying the building at the beginning of the business day.
Another control system may be a controller for causing a population of insecticide sprayers to dispense a spray of insecticide approximately at dusk and periodically thereafter at an amusement park, zoo, of other public place.
Lighting systems provide perhaps the most widespread and easily understood application population control systems. Remote airports, in order to qualify with FAA regulations, or to be entitled to Federal funds, for example, may be required to burn or illuminate runway lights for a time period extending from just before dusk to a couple of hours after sundown. To conserve energy, highway interchanges including intersections, entrance ramps and exist ramps may only need to be illuminated for a time period after dark and then again for a period before dawn, instead of all night long. If the on and off times for highway street lamps are carefully controlled to follow the time of sunset and the time of sunrise at a given location instead of a general time of day on the clock, better lighting and energy savings may also be achieved.
In certain agricultural applications, providing artificial lighting at carefully controlled lighted times, in horticultural and animal environments, such as in a hen house, may promote health, or food production, or both.
The present invention relates to control systems, and more particularly to a system whereby programming and reference instructions are conveyed to remote and geographically diverse, individual control units by means of radio transmissions such that the electrical apparatus to be controlled by such units operate in accordance with predetermined operating protocols or modes. The invention allows the operating protocols or modes to be defined with respect to particular times of each day as well as the time of sunset or sunrise for the particular geographic location at which the apparatus is located.
Sign board lighting systems have come into wide use for illuminating outdoor billboards and the like during the time period between sunset and sunrise. Sign boards which require such illumination exist in very diverse locations, such as along highways or on buildings, and often in very remote places. Moreover, sign boards owned and maintained by a major outdoor advertising company can be located hundreds, or even thousands, of miles apart.
Because it is neither necessary nor desirable to continuously illuminate sign boards, sign board lighting systems are operated only during certain, discreet time periods, or in accordance with predetermined lighting protocols. Typically, such lighting protocols are established by contract between an advertiser and the sign board owner, and may, for example, be from sunset to sunrise or from sunset until a certain specified time at night. By accurately conforming the time period during which the lighting system is activated to the protocol required by the contract, the particular location or application, significant savings are realized from decreased electrical power consumption and extended lamp life.
Prior systems for controlling sign board lighting typically utilized photocells, timers or a combination thereof, to regulate the lighting circuitry. Because of inherent deficiencies in these designs, the operation of such sign board lighting control systems was often less than optimum.
For example, since the time of sunset at a particular sign board location varies on a daily basis and therefore cannot be readily established with a conventional timer, photocells were often utilized to activate a sign board lighting system at sunset. However, the photocells proved to be a crude means of determining the time of sunset, because variations in atmospheric conditions caused the light intensity measured by the photocells at the time of actual sunset to fluctuate dramatically. Thus, on cloudy days such systems would sometimes illuminate the sign board long before sunset. This was an even greater problem in areas where the photocell lens became dirty or otherwise obstructed with time.
Often it is required to alter the lighting protocol of a particular signboard, i.e., to change the times each day when the lighting system is to be activated or deactivated. For example, it is common for a contract to require that the sign board lighting system be deactivated at a particular local time each day. In such a case, upon a time change from "standard time" to "daylight savings time," or vice-versa, the mode of operation of the sign board lighting system must be altered to account for the hour time change. Or, for example, the advertiser contracting for the sign board may decide that the sign should remain illuminated to a later time, say midnight instead of 10 p.m. Or, upon the expiration of the advertising contract, the owner of the sign board may wish to completely discontinue illuminating the sign board until a new advertiser is secured.
In order to alter the lighting protocol of prior sign board illumination systems it was necessary for a repair crew to visit the sign board and control unit site. Because of the diverse, remote and often virtually inaccessible location of many sign boards, this was often an arduous, time-consuming and expensive task.
Certain prior sign board lighting control systems utilized radio transmissions to actuate the systems. The sign boards were categorized into groups of one or more sign boards and turned on or off as a group in response to radio signals. Where a large number of geographically separated sign boards exist, such systems are not practical because of the high cost and time required to send individual radio signals to each sign board or group of sign boards. Moreover, as with sign boards controlled by photocells and timers, such prior sign board lighting control systems did not provide the capability to remotely program the lighting protocol of individual sign boards.
It has been proposed that a control system be developed whereby individual sign boards may be controlled by radio signals. However, such a system would prove unduly expensive because major sign board companies own thousands of sign boards. Since each individual electrical apparatus would require its own transmissions, an excessive number of transmissions would be necessary to effectively control the system.
The present invention overcomes these drawbacks by providing a system whereby both programming and timing signals are communicated to a control unit associated with an electrical apparatus, such as a sign board lighting control device. In particular, the invention provides for transmissions of coded programming signals which designate a particular lighting or operating protocol to a particular sign board or apparatus. Additionally, the invention provides for timing signals necessary for performing the various different lighting protocols of multiple sign boards to be accomplished by a limited number of universal reference transmissions received by all sign boards.
A control unit associated with an individual sign board lighting system includes a receiver capable of intercepting the radio-transmitted coded programming and timing signals and control circuitry capable of decoding such signals and either storing in memory programming signals or executing functions in response to timing reference signals, or executing functions in response to timing reference signals, as the case may be.
Since the control system is able to reference sunset and sunrise at specific geographic locations, outdoor lighting systems are particularly obvious applications of the invention. However, many other applications, including apparatus which operate without reference to sunset or sunrise would benefit from the present invention. Such applications would benefit from both the timing features as well as the remote programmability of the invention.
According, it is a general object of the present invention to provide a new and improved control system for electrical apparatus.
It is another object of the present invention to provide a new and improved control system for lighting systems and other electrical apparatus wherein the system comprises a computer controlled radio frequency transmitter for transmitting coded programming and timing reference signals to a population of radio frequency receivers associated with individual control units, which signals are utilized by the control units to actuate or deactivate the lighting system or electrical apparatus in response to the coded signals, thus providing remote programming capability which eliminates the need for "on-site" programming.
It is a further object of the present invention to provide a new and improved control system for a variety of electrical apparatus whereby commercially available "paging" or "beeper" systems transmit coded programming or timing reference signals to control units associated with each electrical apparatus. The control units decode the signals and activate or deactivate the electrical apparatus in accordance with the programming and timing reference signals.
It is another object of the present invention to provide a new and improved control system for sign board lighting systems and the like.